diff --git a/Makefile b/Makefile
index 5da2d6076..d15668673 100644
--- a/Makefile
+++ b/Makefile
@@ -165,7 +165,7 @@ nimbus-build-system-nimble-dir:
 .PHONY: librln
 
 LIBRLN_BUILDDIR := $(CURDIR)/vendor/zerokit
-LIBRLN_VERSION := v0.5.1
+LIBRLN_VERSION := v0.7.0
 
 ifeq ($(detected_OS),Windows)
 LIBRLN_FILE := rln.lib
diff --git a/tests/waku_rln_relay/test_rln_group_manager_onchain.nim b/tests/waku_rln_relay/test_rln_group_manager_onchain.nim
index b6fc44e27..25a3166ce 100644
--- a/tests/waku_rln_relay/test_rln_group_manager_onchain.nim
+++ b/tests/waku_rln_relay/test_rln_group_manager_onchain.nim
@@ -3,7 +3,7 @@
 {.push raises: [].}
 
 import
-  std/[options, sequtils, deques],
+  std/[options, sequtils, deques, random],
   results,
   stew/byteutils,
   testutils/unittests,
@@ -13,7 +13,8 @@ import
   web3,
   libp2p/crypto/crypto,
   eth/keys,
-  tests/testlib/testasync
+  tests/testlib/testasync,
+  tests/testlib/testutils
 
 import
   waku/[
@@ -47,7 +48,6 @@ suite "Onchain group manager":
       manager.ethRpc.isSome()
       manager.wakuRlnContract.isSome()
       manager.initialized
-      manager.rlnContractDeployedBlockNumber > 0.Quantity
       manager.rlnRelayMaxMessageLimit == 100
 
   asyncTest "should error on initialization when chainId does not match":
@@ -97,18 +97,13 @@ suite "Onchain group manager":
     echo "---"
 
   asyncTest "should error if contract does not exist":
-    var triggeredError = false
-
     manager.ethContractAddress = "0x0000000000000000000000000000000000000000"
-    manager.onFatalErrorAction = proc(msg: string) {.gcsafe, closure.} =
-      echo "---"
-      discard
-        "Failed to get the deployed block number. Have you set the correct contract address?: No response from the Web3 provider"
-      echo msg
-      echo "---"
-      triggeredError = true
 
-    discard await manager.init()
+    var triggeredError = false
+    try:
+      discard await manager.init()
+    except CatchableError:
+      triggeredError = true
 
     check triggeredError
 
@@ -119,103 +114,71 @@ suite "Onchain group manager":
     (await manager.init()).isErrOr:
       raiseAssert "Expected error when keystore file doesn't exist"
 
-  asyncTest "startGroupSync: should start group sync":
+  asyncTest "trackRootChanges: start tracking roots":
     (await manager.init()).isOkOr:
       raiseAssert $error
-    (await manager.startGroupSync()).isOkOr:
-      raiseAssert $error
+    discard manager.trackRootChanges()
 
-  asyncTest "startGroupSync: should guard against uninitialized state":
-    (await manager.startGroupSync()).isErrOr:
-      raiseAssert "Expected error when not initialized"
+  asyncTest "trackRootChanges: should guard against uninitialized state":
+    try:
+      discard manager.trackRootChanges()
+    except CatchableError:
+      check getCurrentExceptionMsg().len == 38
 
-  asyncTest "startGroupSync: should sync to the state of the group":
+  asyncTest "trackRootChanges: should sync to the state of the group":
     let credentials = generateCredentials(manager.rlnInstance)
-    let rateCommitment = getRateCommitment(credentials, UserMessageLimit(1)).valueOr:
-      raiseAssert $error
     (await manager.init()).isOkOr:
       raiseAssert $error
 
-    let merkleRootBefore = manager.rlnInstance.getMerkleRoot().valueOr:
-      raiseAssert $error
-
-    let fut = newFuture[void]("startGroupSync")
-
-    proc generateCallback(fut: Future[void]): OnRegisterCallback =
-      proc callback(registrations: seq[Membership]): Future[void] {.async.} =
-        check:
-          registrations.len == 1
-          registrations[0].index == 0
-          registrations[0].rateCommitment == rateCommitment
-        fut.complete()
-
-      return callback
+    let merkleRootBefore = manager.fetchMerkleRoot()
 
     try:
-      manager.onRegister(generateCallback(fut))
       await manager.register(credentials, UserMessageLimit(1))
-      (await manager.startGroupSync()).isOkOr:
-        raiseAssert $error
     except Exception, CatchableError:
       assert false, "exception raised: " & getCurrentExceptionMsg()
 
-    await fut
+    discard await withTimeout(trackRootChanges(manager), 15.seconds)
 
-    let merkleRootAfter = manager.rlnInstance.getMerkleRoot().valueOr:
+    let merkleRootAfter = manager.fetchMerkleRoot()
+
+    let metadataSetRes = manager.setMetadata()
+    assert metadataSetRes.isOk(), metadataSetRes.error
+
+    let metadataOpt = getMetadata(manager.rlnInstance).valueOr:
       raiseAssert $error
 
-    let metadataOpt = manager.rlnInstance.getMetadata().valueOr:
-      raiseAssert $error
+    assert metadataOpt.isSome(), "metadata is not set"
+    let metadata = metadataOpt.get()
+
     check:
-      metadataOpt.get().validRoots == manager.validRoots.toSeq()
+      metadata.validRoots == manager.validRoots.toSeq()
       merkleRootBefore != merkleRootAfter
 
-  asyncTest "startGroupSync: should fetch history correctly":
+  asyncTest "trackRootChanges: should fetch history correctly":
+    # TODO: We can't use `trackRootChanges()` directly in this test because its current implementation
+    #       relies on a busy loop rather than event-based monitoring. As a result, some root changes
+    #       may be missed, leading to inconsistent test results (i.e., it may randomly return true or false).
+    #       To ensure reliability, we use the `updateRoots()` function to validate the `validRoots` window
+    #       after each registration. 
     const credentialCount = 6
     let credentials = generateCredentials(manager.rlnInstance, credentialCount)
     (await manager.init()).isOkOr:
       raiseAssert $error
 
-    let merkleRootBefore = manager.rlnInstance.getMerkleRoot().valueOr:
-      raiseAssert $error
-
-    type TestGroupSyncFuts = array[0 .. credentialCount - 1, Future[void]]
-    var futures: TestGroupSyncFuts
-    for i in 0 ..< futures.len():
-      futures[i] = newFuture[void]()
-    proc generateCallback(
-        futs: TestGroupSyncFuts, credentials: seq[IdentityCredential]
-    ): OnRegisterCallback =
-      var futureIndex = 0
-      proc callback(registrations: seq[Membership]): Future[void] {.async.} =
-        let rateCommitment =
-          getRateCommitment(credentials[futureIndex], UserMessageLimit(1))
-        if registrations.len == 1 and
-            registrations[0].rateCommitment == rateCommitment.get() and
-            registrations[0].index == MembershipIndex(futureIndex):
-          futs[futureIndex].complete()
-          futureIndex += 1
-
-      return callback
+    let merkleRootBefore = manager.fetchMerkleRoot()
 
     try:
-      manager.onRegister(generateCallback(futures, credentials))
-      (await manager.startGroupSync()).isOkOr:
-        raiseAssert $error
-
       for i in 0 ..< credentials.len():
         await manager.register(credentials[i], UserMessageLimit(1))
+        discard await manager.updateRoots()
     except Exception, CatchableError:
       assert false, "exception raised: " & getCurrentExceptionMsg()
 
-    await allFutures(futures)
-
-    let merkleRootAfter = manager.rlnInstance.getMerkleRoot().valueOr:
-      raiseAssert $error
+    let merkleRootAfter = manager.fetchMerkleRoot()
 
     check:
       merkleRootBefore != merkleRootAfter
-      manager.validRootBuffer.len() == credentialCount - AcceptableRootWindowSize
+      manager.validRoots.len() == credentialCount
 
   asyncTest "register: should guard against uninitialized state":
     let dummyCommitment = default(IDCommitment)
@@ -232,14 +195,12 @@ suite "Onchain group manager":
       assert false, "exception raised: " & getCurrentExceptionMsg()
 
   asyncTest "register: should register successfully":
+    # TODO :- similar to ```trackRootChanges: should fetch history correctly```
     (await manager.init()).isOkOr:
       raiseAssert $error
-    (await manager.startGroupSync()).isOkOr:
-      raiseAssert $error
 
     let idCommitment = generateCredentials(manager.rlnInstance).idCommitment
-    let merkleRootBefore = manager.rlnInstance.getMerkleRoot().valueOr:
-      raiseAssert $error
+    let merkleRootBefore = manager.fetchMerkleRoot()
 
     try:
       await manager.register(
@@ -251,10 +212,10 @@ suite "Onchain group manager":
       assert false,
         "exception raised when calling register: " & getCurrentExceptionMsg()
 
-    let merkleRootAfter = manager.rlnInstance.getMerkleRoot().valueOr:
-      raiseAssert $error
+    let merkleRootAfter = manager.fetchMerkleRoot()
+
     check:
-      merkleRootAfter.inHex() != merkleRootBefore.inHex()
+      merkleRootAfter != merkleRootBefore
       manager.latestIndex == 1
 
   asyncTest "register: callback is called":
@@ -264,19 +225,19 @@ suite "Onchain group manager":
     let fut = newFuture[void]()
 
     proc callback(registrations: seq[Membership]): Future[void] {.async.} =
-      let rateCommitment = getRateCommitment(idCredentials, UserMessageLimit(1))
+      let rateCommitment = getRateCommitment(idCredentials, UserMessageLimit(1)).get()
       check:
         registrations.len == 1
-        registrations[0].rateCommitment == rateCommitment.get()
+        registrations[0].rateCommitment == rateCommitment
         registrations[0].index == 0
       fut.complete()
 
-    manager.onRegister(callback)
     (await manager.init()).isOkOr:
       raiseAssert $error
+
+    manager.onRegister(callback)
+
     try:
-      (await manager.startGroupSync()).isOkOr:
-        raiseAssert $error
       await manager.register(
         RateCommitment(
           idCommitment: idCommitment, userMessageLimit: UserMessageLimit(1)
@@ -298,38 +259,43 @@ suite "Onchain group manager":
       assert false, "exception raised: " & getCurrentExceptionMsg()
 
   asyncTest "validateRoot: should validate good root":
-    let credentials = generateCredentials(manager.rlnInstance)
-    (await manager.init()).isOkOr:
-      raiseAssert $error
+    let idCredentials = generateCredentials(manager.rlnInstance)
+    let idCommitment = idCredentials.idCommitment
 
     let fut = newFuture[void]()
 
     proc callback(registrations: seq[Membership]): Future[void] {.async.} =
       if registrations.len == 1 and
           registrations[0].rateCommitment ==
-          getRateCommitment(credentials, UserMessageLimit(1)).get() and
+          getRateCommitment(idCredentials, UserMessageLimit(1)).get() and
           registrations[0].index == 0:
-        manager.idCredentials = some(credentials)
+        manager.idCredentials = some(idCredentials)
         fut.complete()
 
     manager.onRegister(callback)
 
+    (await manager.init()).isOkOr:
+      raiseAssert $error
+
     try:
-      (await manager.startGroupSync()).isOkOr:
-        raiseAssert $error
-      await manager.register(credentials, UserMessageLimit(1))
+      await manager.register(idCredentials, UserMessageLimit(1))
     except Exception, CatchableError:
       assert false, "exception raised: " & getCurrentExceptionMsg()
 
     await fut
 
+    let rootUpdated = await manager.updateRoots()
+
+    if rootUpdated:
+      let proofResult = await manager.fetchMerkleProofElements()
+      if proofResult.isErr():
+        error "Failed to fetch Merkle proof", error = proofResult.error
+      manager.merkleProofCache = proofResult.get()
     let messageBytes = "Hello".toBytes()
 
-    # prepare the epoch
     let epoch = default(Epoch)
     debug "epoch in bytes", epochHex = epoch.inHex()
 
-    # generate proof
     let validProofRes = manager.generateProof(
       data = messageBytes, epoch = epoch, messageId = MessageId(1)
     )
@@ -338,38 +304,39 @@ suite "Onchain group manager":
       validProofRes.isOk()
     let validProof = validProofRes.get()
 
-    # validate the root (should be true)
     let validated = manager.validateRoot(validProof.merkleRoot)
 
     check:
       validated
 
   asyncTest "validateRoot: should reject bad root":
+    let idCredentials = generateCredentials(manager.rlnInstance)
+    let idCommitment = idCredentials.idCommitment
+
     (await manager.init()).isOkOr:
       raiseAssert $error
-    (await manager.startGroupSync()).isOkOr:
-      raiseAssert $error
 
-    let credentials = generateCredentials(manager.rlnInstance)
-
-    ## Assume the registration occured out of band
-    manager.idCredentials = some(credentials)
-    manager.membershipIndex = some(MembershipIndex(0))
     manager.userMessageLimit = some(UserMessageLimit(1))
+    manager.membershipIndex = some(MembershipIndex(0))
+    manager.idCredentials = some(idCredentials)
+
+    manager.merkleProofCache = newSeq[byte](640)
+    for i in 0 ..< 640:
+      manager.merkleProofCache[i] = byte(rand(255))
 
     let messageBytes = "Hello".toBytes()
 
-    # prepare the epoch
     let epoch = default(Epoch)
     debug "epoch in bytes", epochHex = epoch.inHex()
 
-    # generate proof
-    let validProof = manager.generateProof(
-      data = messageBytes, epoch = epoch, messageId = MessageId(0)
-    ).valueOr:
-      raiseAssert $error
+    let validProofRes = manager.generateProof(
+      data = messageBytes, epoch = epoch, messageId = MessageId(1)
+    )
+
+    check:
+      validProofRes.isOk()
+    let validProof = validProofRes.get()
 
-    # validate the root (should be false)
     let validated = manager.validateRoot(validProof.merkleRoot)
 
     check:
@@ -393,13 +360,19 @@ suite "Onchain group manager":
     manager.onRegister(callback)
 
     try:
-      (await manager.startGroupSync()).isOkOr:
-        raiseAssert $error
       await manager.register(credentials, UserMessageLimit(1))
     except Exception, CatchableError:
       assert false, "exception raised: " & getCurrentExceptionMsg()
     await fut
 
+    let rootUpdated = await manager.updateRoots()
+
+    if rootUpdated:
+      let proofResult = await manager.fetchMerkleProofElements()
+      if proofResult.isErr():
+        error "Failed to fetch Merkle proof", error = proofResult.error
+      manager.merkleProofCache = proofResult.get()
+
     let messageBytes = "Hello".toBytes()
 
     # prepare the epoch
@@ -412,7 +385,6 @@ suite "Onchain group manager":
     ).valueOr:
       raiseAssert $error
 
-    # verify the proof (should be true)
     let verified = manager.verifyProof(messageBytes, validProof).valueOr:
       raiseAssert $error
 
@@ -422,31 +394,23 @@ suite "Onchain group manager":
   asyncTest "verifyProof: should reject invalid proof":
     (await manager.init()).isOkOr:
       raiseAssert $error
-    (await manager.startGroupSync()).isOkOr:
-      raiseAssert $error
 
     let idCredential = generateCredentials(manager.rlnInstance)
 
     try:
-      await manager.register(
-        RateCommitment(
-          idCommitment: idCredential.idCommitment, userMessageLimit: UserMessageLimit(1)
-        )
-      )
+      await manager.register(idCredential, UserMessageLimit(1))
     except Exception, CatchableError:
       assert false,
         "exception raised when calling startGroupSync: " & getCurrentExceptionMsg()
 
-    let idCredential2 = generateCredentials(manager.rlnInstance)
-
-    ## Assume the registration occured out of band
-    manager.idCredentials = some(idCredential2)
-    manager.membershipIndex = some(MembershipIndex(0))
-    manager.userMessageLimit = some(UserMessageLimit(1))
-
     let messageBytes = "Hello".toBytes()
 
-    # prepare the epoch
+    let rootUpdated = await manager.updateRoots()
+
+    manager.merkleProofCache = newSeq[byte](640)
+    for i in 0 ..< 640:
+      manager.merkleProofCache[i] = byte(rand(255))
+
     let epoch = default(Epoch)
     debug "epoch in bytes", epochHex = epoch.inHex()
 
@@ -466,8 +430,8 @@ suite "Onchain group manager":
     check:
       verified == false
 
-  asyncTest "backfillRootQueue: should backfill roots in event of chain reorg":
-    const credentialCount = 6
+  asyncTest "root queue should be updated correctly":
+    const credentialCount = 12
     let credentials = generateCredentials(manager.rlnInstance, credentialCount)
     (await manager.init()).isOkOr:
       raiseAssert $error
@@ -493,33 +457,17 @@ suite "Onchain group manager":
 
     try:
       manager.onRegister(generateCallback(futures, credentials))
-      (await manager.startGroupSync()).isOkOr:
-        raiseAssert $error
 
       for i in 0 ..< credentials.len():
         await manager.register(credentials[i], UserMessageLimit(1))
+        discard await manager.updateRoots()
     except Exception, CatchableError:
       assert false, "exception raised: " & getCurrentExceptionMsg()
 
     await allFutures(futures)
 
-    # At this point, we should have a full root queue, 5 roots, and partial buffer of 1 root
     check:
-      manager.validRoots.len() == credentialCount - 1
-      manager.validRootBuffer.len() == 1
-
-    # We can now simulate a chain reorg by calling backfillRootQueue
-    let expectedLastRoot = manager.validRootBuffer[0]
-    try:
-      await manager.backfillRootQueue(1)
-    except Exception, CatchableError:
-      assert false, "exception raised: " & getCurrentExceptionMsg()
-
-    # We should now have 5 roots in the queue, and no partial buffer
-    check:
-      manager.validRoots.len() == credentialCount - 1
-      manager.validRootBuffer.len() == 0
-      manager.validRoots[credentialCount - 2] == expectedLastRoot
+      manager.validRoots.len() == credentialCount
 
   asyncTest "isReady should return false if ethRpc is none":
     (await manager.init()).isOkOr:
@@ -536,25 +484,9 @@ suite "Onchain group manager":
     check:
       isReady == false
 
-  asyncTest "isReady should return false if lastSeenBlockHead > lastProcessed":
-    (await manager.init()).isOkOr:
-      raiseAssert $error
-
-    var isReady = true
-    try:
-      isReady = await manager.isReady()
-    except Exception, CatchableError:
-      assert false, "exception raised: " & getCurrentExceptionMsg()
-
-    check:
-      isReady == false
-
   asyncTest "isReady should return true if ethRpc is ready":
     (await manager.init()).isOkOr:
       raiseAssert $error
-    # node can only be ready after group sync is done
-    (await manager.startGroupSync()).isOkOr:
-      raiseAssert $error
 
     var isReady = false
     try:
diff --git a/tests/waku_rln_relay/test_wakunode_rln_relay.nim b/tests/waku_rln_relay/test_wakunode_rln_relay.nim
index a5237dab1..3ff6923e0 100644
--- a/tests/waku_rln_relay/test_wakunode_rln_relay.nim
+++ b/tests/waku_rln_relay/test_wakunode_rln_relay.nim
@@ -529,7 +529,6 @@ procSuite "WakuNode - RLN relay":
 
   xasyncTest "clearNullifierLog: should clear epochs > MaxEpochGap":
     ## This is skipped because is flaky and made CI randomly fail but is useful to run manually
-
     # Given two nodes
     let
       contentTopic = ContentTopic("/waku/2/default-content/proto")
diff --git a/vendor/zerokit b/vendor/zerokit
index b9d27039c..ba467d370 160000
--- a/vendor/zerokit
+++ b/vendor/zerokit
@@ -1 +1 @@
-Subproject commit b9d27039c3266af108882d7a8bafc37400d29855
+Subproject commit ba467d370c56b7432522227de22fbd664d44ef3e
diff --git a/waku/waku_rln_relay/conversion_utils.nim b/waku/waku_rln_relay/conversion_utils.nim
index e710fea62..4a168ebeb 100644
--- a/waku/waku_rln_relay/conversion_utils.nim
+++ b/waku/waku_rln_relay/conversion_utils.nim
@@ -27,9 +27,6 @@ proc inHex*(
     valueHex = "0" & valueHex
   return toLowerAscii(valueHex)
 
-proc toUserMessageLimit*(v: UInt256): UserMessageLimit =
-  return cast[UserMessageLimit](v)
-
 proc encodeLengthPrefix*(input: openArray[byte]): seq[byte] =
   ## returns length prefixed version of the input
   ## with the following format [len<8>|input<var>]
@@ -78,6 +75,31 @@ proc serialize*(
   )
   return output
 
+proc serialize*(witness: RLNWitnessInput): seq[byte] =
+  ## Serializes the RLN witness into a byte array following zerokit's expected format.
+  ## The serialized format includes:
+  ## - identity_secret (32 bytes, little-endian with zero padding)
+  ## - user_message_limit (32 bytes, little-endian with zero padding)
+  ## - message_id (32 bytes, little-endian with zero padding)
+  ## - merkle tree depth (8 bytes, little-endian) = path_elements.len / 32
+  ## - path_elements (each 32 bytes, ordered bottom-to-top)
+  ## - merkle tree depth again (8 bytes, little-endian)
+  ## - identity_path_index (sequence of bits as bytes, 0 = left, 1 = right)
+  ## - x (32 bytes, little-endian with zero padding)
+  ## - external_nullifier (32 bytes, little-endian with zero padding)
+  var buffer: seq[byte]
+  buffer.add(@(witness.identity_secret))
+  buffer.add(@(witness.user_message_limit))
+  buffer.add(@(witness.message_id))
+  buffer.add(toBytes(uint64(witness.path_elements.len / 32), Endianness.littleEndian))
+  for element in witness.path_elements:
+    buffer.add(element)
+  buffer.add(toBytes(uint64(witness.path_elements.len / 32), Endianness.littleEndian))
+  buffer.add(witness.identity_path_index)
+  buffer.add(@(witness.x))
+  buffer.add(@(witness.external_nullifier))
+  return buffer
+
 proc serialize*(proof: RateLimitProof, data: openArray[byte]): seq[byte] =
   ## a private proc to convert RateLimitProof and data to a byte seq
   ## this conversion is used in the proof verification proc
@@ -133,3 +155,25 @@ func `+`*(a, b: Quantity): Quantity {.borrow.}
 
 func u256*(n: Quantity): UInt256 {.inline.} =
   n.uint64.stuint(256)
+
+proc uint64ToField*(n: uint64): array[32, byte] =
+  var output: array[32, byte]
+  let bytes = toBytes(n, Endianness.littleEndian)
+  output[0 ..< bytes.len] = bytes
+  return output
+
+proc UInt256ToField*(v: UInt256): array[32, byte] =
+  return cast[array[32, byte]](v) # already doesn't use `result`
+
+proc seqToField*(s: seq[byte]): array[32, byte] =
+  var output: array[32, byte]
+  let len = min(s.len, 32)
+  for i in 0 ..< len:
+    output[i] = s[i]
+  return output
+
+proc uint64ToIndex*(index: MembershipIndex, depth: int): seq[byte] =
+  var output = newSeq[byte](depth)
+  for i in 0 ..< depth:
+    output[i] = byte((index shr i) and 1) # LSB-first bit decomposition
+  return output
diff --git a/waku/waku_rln_relay/group_manager/group_manager_base.nim b/waku/waku_rln_relay/group_manager/group_manager_base.nim
index 818b36140..4a1c84e55 100644
--- a/waku/waku_rln_relay/group_manager/group_manager_base.nim
+++ b/waku/waku_rln_relay/group_manager/group_manager_base.nim
@@ -145,7 +145,6 @@ method validateRoot*(
     g: GroupManager, root: MerkleNode
 ): bool {.base, gcsafe, raises: [].} =
   ## validates the root against the valid roots queue
-  # Check if the root is in the valid roots queue
   if g.indexOfRoot(root) >= 0:
     return true
   return false
@@ -175,7 +174,7 @@ method verifyProof*(
 
 method generateProof*(
     g: GroupManager,
-    data: openArray[byte],
+    data: seq[byte],
     epoch: Epoch,
     messageId: MessageId,
     rlnIdentifier = DefaultRlnIdentifier,
@@ -189,6 +188,7 @@ method generateProof*(
     return err("membership index is not set")
   if g.userMessageLimit.isNone():
     return err("user message limit is not set")
+
   waku_rln_proof_generation_duration_seconds.nanosecondTime:
     let proof = proofGen(
       rlnInstance = g.rlnInstance,
@@ -201,8 +201,6 @@ method generateProof*(
     ).valueOr:
       return err("proof generation failed: " & $error)
 
-  waku_rln_remaining_proofs_per_epoch.dec()
-  waku_rln_total_generated_proofs.inc()
   return ok(proof)
 
 method isReady*(g: GroupManager): Future[bool] {.base, async.} =
diff --git a/waku/waku_rln_relay/group_manager/on_chain/group_manager.nim b/waku/waku_rln_relay/group_manager/on_chain/group_manager.nim
index e61ffb956..fe3db9102 100644
--- a/waku/waku_rln_relay/group_manager/on_chain/group_manager.nim
+++ b/waku/waku_rln_relay/group_manager/on_chain/group_manager.nim
@@ -10,19 +10,18 @@ import
   nimcrypto/keccak as keccak,
   stint,
   json,
-  std/tables,
+  std/[strutils, tables, algorithm],
   stew/[byteutils, arrayops],
-  sequtils,
-  strutils
+  sequtils
+
 import
   ../../../waku_keystore,
   ../../rln,
+  ../../rln/rln_interface,
   ../../conversion_utils,
   ../group_manager_base,
   ./retry_wrapper
 
-from strutils import parseHexInt
-
 export group_manager_base
 
 logScope:
@@ -31,19 +30,23 @@ logScope:
 # using the when predicate does not work within the contract macro, hence need to dupe
 contract(WakuRlnContract):
   # this serves as an entrypoint into the rln membership set
-  proc register(idCommitment: UInt256, userMessageLimit: EthereumUInt32)
+  proc register(idCommitment: UInt256, userMessageLimit: UInt32)
   # Initializes the implementation contract (only used in unit tests)
   proc initialize(maxMessageLimit: UInt256)
   # this event is raised when a new member is registered
-  proc MemberRegistered(rateCommitment: UInt256, index: EthereumUInt32) {.event.}
+  proc MemberRegistered(rateCommitment: UInt256, index: UInt32) {.event.}
   # this function denotes existence of a given user
-  proc memberExists(idCommitment: Uint256): UInt256 {.view.}
+  proc memberExists(idCommitment: UInt256): UInt256 {.view.}
   # this constant describes the next index of a new member
   proc commitmentIndex(): UInt256 {.view.}
   # this constant describes the block number this contract was deployed on
   proc deployedBlockNumber(): UInt256 {.view.}
   # this constant describes max message limit of rln contract
   proc MAX_MESSAGE_LIMIT(): UInt256 {.view.}
+  # this function returns the merkleProof for a given index 
+  # proc merkleProofElements(index: UInt40): seq[byte] {.view.}
+  # this function returns the merkle root 
+  proc root(): UInt256 {.view.}
 
 type
   WakuRlnContractWithSender = Sender[WakuRlnContract]
@@ -52,42 +55,14 @@ type
     ethPrivateKey*: Option[string]
     ethContractAddress*: string
     ethRpc*: Option[Web3]
-    rlnContractDeployedBlockNumber*: BlockNumber
     wakuRlnContract*: Option[WakuRlnContractWithSender]
-    latestProcessedBlock*: BlockNumber
     registrationTxHash*: Option[TxHash]
     chainId*: uint
     keystorePath*: Option[string]
     keystorePassword*: Option[string]
     registrationHandler*: Option[RegistrationHandler]
-    # this buffer exists to backfill appropriate roots for the merkle tree,
-    # in event of a reorg. we store 5 in the buffer. Maybe need to revisit this,
-    # because the average reorg depth is 1 to 2 blocks.
-    validRootBuffer*: Deque[MerkleNode]
-    # interval loop to shut down gracefully
-    blockFetchingActive*: bool
-
-const DefaultKeyStorePath* = "rlnKeystore.json"
-const DefaultKeyStorePassword* = "password"
-
-const DefaultBlockPollRate* = 6.seconds
-
-template initializedGuard(g: OnchainGroupManager): untyped =
-  if not g.initialized:
-    raise newException(CatchableError, "OnchainGroupManager is not initialized")
-
-proc resultifiedInitGuard(g: OnchainGroupManager): GroupManagerResult[void] =
-  try:
-    initializedGuard(g)
-    return ok()
-  except CatchableError:
-    return err("OnchainGroupManager is not initialized")
-
-template retryWrapper(
-    g: OnchainGroupManager, res: auto, errStr: string, body: untyped
-): auto =
-  retryWrapper(res, RetryStrategy.new(), errStr, g.onFatalErrorAction):
-    body
+    latestProcessedBlock*: BlockNumber
+    merkleProofCache*: seq[byte]
 
 proc setMetadata*(
     g: OnchainGroupManager, lastProcessedBlock = none(BlockNumber)
@@ -112,33 +87,109 @@ proc setMetadata*(
     return err("failed to persist rln metadata: " & getCurrentExceptionMsg())
   return ok()
 
-method atomicBatch*(
-    g: OnchainGroupManager,
-    start: MembershipIndex,
-    rateCommitments = newSeq[RawRateCommitment](),
-    toRemoveIndices = newSeq[MembershipIndex](),
-): Future[void] {.async: (raises: [Exception]), base.} =
-  initializedGuard(g)
+proc fetchMerkleProofElements*(
+    g: OnchainGroupManager
+): Future[Result[seq[byte], string]] {.async.} =
+  try:
+    let membershipIndex = g.membershipIndex.get()
+    let index40 = stuint(membershipIndex, 40)
 
-  waku_rln_membership_insertion_duration_seconds.nanosecondTime:
-    let operationSuccess =
-      g.rlnInstance.atomicWrite(some(start), rateCommitments, toRemoveIndices)
-  if not operationSuccess:
-    raise newException(CatchableError, "atomic batch operation failed")
-  # TODO: when slashing is enabled, we need to track slashed members
-  waku_rln_number_registered_memberships.set(int64(g.rlnInstance.leavesSet()))
+    let methodSig = "merkleProofElements(uint40)"
+    let methodIdDigest = keccak.keccak256.digest(methodSig)
+    let methodId = methodIdDigest.data[0 .. 3]
 
-  if g.registerCb.isSome():
-    var membersSeq = newSeq[Membership]()
-    for i in 0 ..< rateCommitments.len:
-      var index = start + MembershipIndex(i)
-      debug "registering member to callback",
-        rateCommitment = rateCommitments[i], index = index
-      let member = Membership(rateCommitment: rateCommitments[i], index: index)
-      membersSeq.add(member)
-    await g.registerCb.get()(membersSeq)
+    var paddedParam = newSeq[byte](32)
+    let indexBytes = index40.toBytesBE()
+    for i in 0 ..< min(indexBytes.len, paddedParam.len):
+      paddedParam[paddedParam.len - indexBytes.len + i] = indexBytes[i]
 
-  g.validRootBuffer = g.slideRootQueue()
+    var callData = newSeq[byte]()
+    for b in methodId:
+      callData.add(b)
+    callData.add(paddedParam)
+
+    var tx: TransactionArgs
+    tx.to = Opt.some(fromHex(Address, g.ethContractAddress))
+    tx.data = Opt.some(callData)
+
+    let responseBytes = await g.ethRpc.get().provider.eth_call(tx, "latest")
+
+    return ok(responseBytes)
+  except CatchableError:
+    error "Failed to fetch Merkle proof elements", error = getCurrentExceptionMsg()
+    return err("Failed to fetch merkle proof elements: " & getCurrentExceptionMsg())
+
+proc fetchMerkleRoot*(
+    g: OnchainGroupManager
+): Future[Result[UInt256, string]] {.async.} =
+  try:
+    let merkleRootInvocation = g.wakuRlnContract.get().root()
+    let merkleRoot = await merkleRootInvocation.call()
+    return ok(merkleRoot)
+  except CatchableError:
+    error "Failed to fetch Merkle root", error = getCurrentExceptionMsg()
+    return err("Failed to fetch merkle root: " & getCurrentExceptionMsg())
+
+template initializedGuard(g: OnchainGroupManager): untyped =
+  if not g.initialized:
+    raise newException(CatchableError, "OnchainGroupManager is not initialized")
+
+template retryWrapper(
+    g: OnchainGroupManager, res: auto, errStr: string, body: untyped
+): auto =
+  retryWrapper(res, RetryStrategy.new(), errStr, g.onFatalErrorAction):
+    body
+
+method validateRoot*(g: OnchainGroupManager, root: MerkleNode): bool =
+  if g.validRoots.find(root) >= 0:
+    return true
+  return false
+
+proc updateRoots*(g: OnchainGroupManager): Future[bool] {.async.} =
+  let rootRes = await g.fetchMerkleRoot()
+  if rootRes.isErr():
+    return false
+
+  let merkleRoot = UInt256ToField(rootRes.get())
+  if g.validRoots.len == 0:
+    g.validRoots.addLast(merkleRoot)
+    return true
+
+  if g.validRoots[g.validRoots.len - 1] != merkleRoot:
+    if g.validRoots.len > AcceptableRootWindowSize:
+      discard g.validRoots.popFirst()
+    g.validRoots.addLast(merkleRoot)
+    return true
+
+  return false
+
+proc trackRootChanges*(g: OnchainGroupManager) {.async: (raises: [CatchableError]).} =
+  try:
+    initializedGuard(g)
+    let ethRpc = g.ethRpc.get()
+    let wakuRlnContract = g.wakuRlnContract.get()
+
+    const rpcDelay = 5.seconds
+
+    while true:
+      let rootUpdated = await g.updateRoots()
+
+      if rootUpdated:
+        if g.membershipIndex.isNone():
+          error "membershipIndex is not set; skipping proof update"
+        else:
+          let proofResult = await g.fetchMerkleProofElements()
+          if proofResult.isErr():
+            error "Failed to fetch Merkle proof", error = proofResult.error
+          g.merkleProofCache = proofResult.get()
+
+        # also need update registerd membership
+        let memberCount = cast[int64](await wakuRlnContract.commitmentIndex().call())
+        waku_rln_number_registered_memberships.set(float64(memberCount))
+
+      await sleepAsync(rpcDelay)
+  except CatchableError:
+    error "Fatal error in trackRootChanges", error = getCurrentExceptionMsg()
 
 method register*(
     g: OnchainGroupManager, rateCommitment: RateCommitment
@@ -147,18 +198,14 @@ method register*(
 
   try:
     let leaf = rateCommitment.toLeaf().get()
-    await g.registerBatch(@[leaf])
+    if g.registerCb.isSome():
+      let idx = g.latestIndex
+      debug "registering member via callback", rateCommitment = leaf, index = idx
+      await g.registerCb.get()(@[Membership(rateCommitment: leaf, index: idx)])
+    g.latestIndex.inc()
   except CatchableError:
     raise newException(ValueError, getCurrentExceptionMsg())
 
-method registerBatch*(
-    g: OnchainGroupManager, rateCommitments: seq[RawRateCommitment]
-): Future[void] {.async: (raises: [Exception]).} =
-  initializedGuard(g)
-
-  await g.atomicBatch(g.latestIndex, rateCommitments)
-  g.latestIndex += MembershipIndex(rateCommitments.len)
-
 method register*(
     g: OnchainGroupManager,
     identityCredential: IdentityCredential,
@@ -212,8 +259,19 @@ method register*(
   debug "parsed membershipIndex", membershipIndex
   g.userMessageLimit = some(userMessageLimit)
   g.membershipIndex = some(membershipIndex.toMembershipIndex())
+  g.idCredentials = some(identityCredential)
+
+  let rateCommitment = RateCommitment(
+      idCommitment: identityCredential.idCommitment, userMessageLimit: userMessageLimit
+    )
+    .toLeaf()
+    .get()
+
+  if g.registerCb.isSome():
+    let member = Membership(rateCommitment: rateCommitment, index: g.latestIndex)
+    await g.registerCb.get()(@[member])
+  g.latestIndex.inc()
 
-  # don't handle member insertion into the tree here, it will be handled by the event listener
   return
 
 method withdraw*(
@@ -226,304 +284,173 @@ method withdrawBatch*(
 ): Future[void] {.async: (raises: [Exception]).} =
   initializedGuard(g)
 
-    # TODO: after slashing is enabled on the contract, use atomicBatch internally
+proc getRootFromProofAndIndex(
+    g: OnchainGroupManager, elements: seq[byte], bits: seq[byte]
+): GroupManagerResult[array[32, byte]] =
+  # this is a helper function to get root from merkle proof elements and index
+  # it's currently not used anywhere, but can be used to verify the root from the proof and index
+  # Compute leaf hash from idCommitment and messageLimit
+  let messageLimitField = uint64ToField(g.userMessageLimit.get())
+  let leafHashRes = poseidon(@[g.idCredentials.get().idCommitment, @messageLimitField])
+  if leafHashRes.isErr():
+    return err("Failed to compute leaf hash: " & leafHashRes.error)
 
-proc parseEvent(
-    event: type MemberRegistered, log: JsonNode
-): GroupManagerResult[Membership] =
-  ## parses the `data` parameter of the `MemberRegistered` event `log`
-  ## returns an error if it cannot parse the `data` parameter
-  var rateCommitment: UInt256
-  var index: UInt256
-  var data: seq[byte]
-  try:
-    data = hexToSeqByte(log["data"].getStr())
-  except ValueError:
-    return err(
-      "failed to parse the data field of the MemberRegistered event: " &
-        getCurrentExceptionMsg()
-    )
-  var offset = 0
-  try:
-    # Parse the rateCommitment
-    offset += decode(data, 0, offset, rateCommitment)
-    # Parse the index
-    offset += decode(data, 0, offset, index)
-    return ok(
-      Membership(
-        rateCommitment: rateCommitment.toRateCommitment(),
-        index: index.toMembershipIndex(),
-      )
-    )
-  except CatchableError:
-    return err("failed to parse the data field of the MemberRegistered event")
+  var hash = leafHashRes.get()
+  for i in 0 ..< bits.len:
+    let sibling = elements[i * 32 .. (i + 1) * 32 - 1]
 
-type BlockTable* = OrderedTable[BlockNumber, seq[(Membership, bool)]]
+    let hashRes =
+      if bits[i] == 0:
+        poseidon(@[@hash, sibling])
+      else:
+        poseidon(@[sibling, @hash])
 
-proc backfillRootQueue*(
-    g: OnchainGroupManager, len: uint
-): Future[void] {.async: (raises: [Exception]).} =
-  if len > 0:
-    # backfill the tree's acceptable roots
-    for i in 0 .. len - 1:
-      # remove the last root
-      g.validRoots.popLast()
-    for i in 0 .. len - 1:
-      # add the backfilled root
-      g.validRoots.addLast(g.validRootBuffer.popLast())
+    hash = hashRes.valueOr:
+      return err("Failed to compute poseidon hash: " & error)
+    hash = hashRes.get()
 
-proc insert(
-    blockTable: var BlockTable,
-    blockNumber: BlockNumber,
-    member: Membership,
-    removed: bool,
-) =
-  let memberTuple = (member, removed)
-  if blockTable.hasKeyOrPut(blockNumber, @[memberTuple]):
-    try:
-      blockTable[blockNumber].add(memberTuple)
-    except KeyError: # qed
-      error "could not insert member into block table",
-        blockNumber = blockNumber, member = member
+  return ok(hash)
 
-proc getRawEvents(
-    g: OnchainGroupManager, fromBlock: BlockNumber, toBlock: BlockNumber
-): Future[JsonNode] {.async: (raises: [Exception]).} =
-  initializedGuard(g)
+method generateProof*(
+    g: OnchainGroupManager,
+    data: seq[byte],
+    epoch: Epoch,
+    messageId: MessageId,
+    rlnIdentifier = DefaultRlnIdentifier,
+): GroupManagerResult[RateLimitProof] {.gcsafe, raises: [].} =
+  ## Generates an RLN proof using the cached Merkle proof and custom witness
+  # Ensure identity credentials and membership index are set
+  if g.idCredentials.isNone():
+    return err("identity credentials are not set")
+  if g.membershipIndex.isNone():
+    return err("membership index is not set")
+  if g.userMessageLimit.isNone():
+    return err("user message limit is not set")
 
-  let ethRpc = g.ethRpc.get()
-  let wakuRlnContract = g.wakuRlnContract.get()
+  if (g.merkleProofCache.len mod 32) != 0:
+    return err("Invalid merkle proof cache length")
 
-  var eventStrs: seq[JsonString]
-  g.retryWrapper(eventStrs, "Failed to get the events"):
-    await wakuRlnContract.getJsonLogs(
-      MemberRegistered,
-      fromBlock = Opt.some(fromBlock.blockId()),
-      toBlock = Opt.some(toBlock.blockId()),
-    )
+  let identity_secret = seqToField(g.idCredentials.get().idSecretHash)
+  let user_message_limit = uint64ToField(g.userMessageLimit.get())
+  let message_id = uint64ToField(messageId)
+  var path_elements = newSeq[byte](0)
 
-  var events = newJArray()
-  for eventStr in eventStrs:
-    events.add(parseJson(eventStr.string))
-  return events
+  if (g.merkleProofCache.len mod 32) != 0:
+    return err("Invalid merkle proof cache length")
 
-proc getBlockTable(
-    g: OnchainGroupManager, fromBlock: BlockNumber, toBlock: BlockNumber
-): Future[BlockTable] {.async: (raises: [Exception]).} =
-  initializedGuard(g)
+  let identity_path_index = uint64ToIndex(g.membershipIndex.get(), 20)
+  for i in 0 ..< g.merkleProofCache.len div 32:
+    let chunk = g.merkleProofCache[i * 32 .. (i + 1) * 32 - 1]
+    path_elements.add(chunk.reversed())
 
-  var blockTable = default(BlockTable)
+  let x = keccak.keccak256.digest(data)
 
-  let events = await g.getRawEvents(fromBlock, toBlock)
+  let extNullifier = poseidon(@[@(epoch), @(rlnIdentifier)]).valueOr:
+    return err("Failed to compute external nullifier: " & error)
 
-  if events.len == 0:
-    trace "no events found"
-    return blockTable
+  let witness = RLNWitnessInput(
+    identity_secret: identity_secret,
+    user_message_limit: user_message_limit,
+    message_id: message_id,
+    path_elements: path_elements,
+    identity_path_index: identity_path_index,
+    x: x,
+    external_nullifier: extNullifier,
+  )
 
-  for event in events:
-    let blockNumber = parseHexInt(event["blockNumber"].getStr()).BlockNumber
-    let removed = event["removed"].getBool()
-    let parsedEventRes = parseEvent(MemberRegistered, event)
-    if parsedEventRes.isErr():
-      error "failed to parse the MemberRegistered event", error = parsedEventRes.error()
-      raise newException(ValueError, "failed to parse the MemberRegistered event")
-    let parsedEvent = parsedEventRes.get()
-    blockTable.insert(blockNumber, parsedEvent, removed)
+  let serializedWitness = serialize(witness)
 
-  return blockTable
+  var input_witness_buffer = toBuffer(serializedWitness)
 
-proc handleEvents(
-    g: OnchainGroupManager, blockTable: BlockTable
-): Future[void] {.async: (raises: [Exception]).} =
-  initializedGuard(g)
+  # Generate the proof using the zerokit API
+  var output_witness_buffer: Buffer
+  let witness_success = generate_proof_with_witness(
+    g.rlnInstance, addr input_witness_buffer, addr output_witness_buffer
+  )
 
-  for blockNumber, members in blockTable.pairs():
-    try:
-      let startIndex = blockTable[blockNumber].filterIt(not it[1])[0][0].index
-      let removalIndices = members.filterIt(it[1]).mapIt(it[0].index)
-      let rateCommitments = members.mapIt(it[0].rateCommitment)
-      await g.atomicBatch(
-        start = startIndex,
-        rateCommitments = rateCommitments,
-        toRemoveIndices = removalIndices,
-      )
-      g.latestIndex = startIndex + MembershipIndex(rateCommitments.len)
-      trace "new members added to the Merkle tree",
-        commitments = rateCommitments.mapIt(it.inHex)
-    except CatchableError:
-      error "failed to insert members into the tree", error = getCurrentExceptionMsg()
-      raise newException(ValueError, "failed to insert members into the tree")
+  if not witness_success:
+    return err("Failed to generate proof")
 
-  return
+  # Parse the proof into a RateLimitProof object
+  var proofValue = cast[ptr array[320, byte]](output_witness_buffer.`ptr`)
+  let proofBytes: array[320, byte] = proofValue[]
 
-proc handleRemovedEvents(
-    g: OnchainGroupManager, blockTable: BlockTable
-): Future[void] {.async: (raises: [Exception]).} =
-  initializedGuard(g)
+  ## parse the proof as [ proof<128> | root<32> | external_nullifier<32> | share_x<32> | share_y<32> | nullifier<32> ]
+  let
+    proofOffset = 128
+    rootOffset = proofOffset + 32
+    externalNullifierOffset = rootOffset + 32
+    shareXOffset = externalNullifierOffset + 32
+    shareYOffset = shareXOffset + 32
+    nullifierOffset = shareYOffset + 32
 
-  # count number of blocks that have been removed
-  var numRemovedBlocks: uint = 0
-  for blockNumber, members in blockTable.pairs():
-    if members.anyIt(it[1]):
-      numRemovedBlocks += 1
+  var
+    zkproof: ZKSNARK
+    proofRoot, shareX, shareY: MerkleNode
+    externalNullifier: ExternalNullifier
+    nullifier: Nullifier
 
-  await g.backfillRootQueue(numRemovedBlocks)
+  discard zkproof.copyFrom(proofBytes[0 .. proofOffset - 1])
+  discard proofRoot.copyFrom(proofBytes[proofOffset .. rootOffset - 1])
+  discard
+    externalNullifier.copyFrom(proofBytes[rootOffset .. externalNullifierOffset - 1])
+  discard shareX.copyFrom(proofBytes[externalNullifierOffset .. shareXOffset - 1])
+  discard shareY.copyFrom(proofBytes[shareXOffset .. shareYOffset - 1])
+  discard nullifier.copyFrom(proofBytes[shareYOffset .. nullifierOffset - 1])
 
-proc getAndHandleEvents(
-    g: OnchainGroupManager, fromBlock: BlockNumber, toBlock: BlockNumber
-): Future[bool] {.async: (raises: [Exception]).} =
-  initializedGuard(g)
-  let blockTable = await g.getBlockTable(fromBlock, toBlock)
-  try:
-    await g.handleEvents(blockTable)
-    await g.handleRemovedEvents(blockTable)
-  except CatchableError:
-    error "failed to handle events", error = getCurrentExceptionMsg()
-    raise newException(ValueError, "failed to handle events")
+  # Create the RateLimitProof object
+  let output = RateLimitProof(
+    proof: zkproof,
+    merkleRoot: proofRoot,
+    externalNullifier: externalNullifier,
+    epoch: epoch,
+    rlnIdentifier: rlnIdentifier,
+    shareX: shareX,
+    shareY: shareY,
+    nullifier: nullifier,
+  )
 
-  g.latestProcessedBlock = toBlock
-  return true
+  debug "Proof generated successfully"
 
-proc runInInterval(g: OnchainGroupManager, cb: proc, interval: Duration) =
-  g.blockFetchingActive = false
+  waku_rln_remaining_proofs_per_epoch.dec()
+  waku_rln_total_generated_proofs.inc()
+  return ok(output)
 
-  proc runIntervalLoop() {.async, gcsafe.} =
-    g.blockFetchingActive = true
+method verifyProof*(
+    g: OnchainGroupManager, # verifier context
+    input: seq[byte], # raw message data (signal)
+    proof: RateLimitProof, # proof received from the peer
+): GroupManagerResult[bool] {.gcsafe, raises: [].} =
+  ## -- Verifies an RLN rate-limit proof against the set of valid Merkle roots --
 
-    while g.blockFetchingActive:
-      var retCb: bool
-      g.retryWrapper(retCb, "Failed to run the interval block fetching loop"):
-        await cb()
-      await sleepAsync(interval)
+  var normalizedProof = proof
 
-  # using asyncSpawn is OK here since
-  # we make use of the error handling provided by
-  # OnFatalErrorHandler
-  asyncSpawn runIntervalLoop()
+  normalizedProof.externalNullifier = poseidon(
+    @[@(proof.epoch), @(proof.rlnIdentifier)]
+  ).valueOr:
+    return err("Failed to compute external nullifier: " & error)
 
-proc getNewBlockCallback(g: OnchainGroupManager): proc =
-  let ethRpc = g.ethRpc.get()
-  proc wrappedCb(): Future[bool] {.async, gcsafe.} =
-    var latestBlock: BlockNumber
-    g.retryWrapper(latestBlock, "Failed to get the latest block number"):
-      cast[BlockNumber](await ethRpc.provider.eth_blockNumber())
+  let proofBytes = serialize(normalizedProof, input)
+  let proofBuffer = proofBytes.toBuffer()
 
-    if latestBlock <= g.latestProcessedBlock:
-      return
-    # get logs from the last block
-    # inc by 1 to prevent double processing
-    let fromBlock = g.latestProcessedBlock + 1
-    var handleBlockRes: bool
-    g.retryWrapper(handleBlockRes, "Failed to handle new block"):
-      await g.getAndHandleEvents(fromBlock, latestBlock)
+  let rootsBytes = serialize(g.validRoots.items().toSeq())
+  let rootsBuffer = rootsBytes.toBuffer()
 
-    # cannot use isOkOr here because results in a compile-time error that
-    # shows the error is void for some reason
-    let setMetadataRes = g.setMetadata()
-    if setMetadataRes.isErr():
-      error "failed to persist rln metadata", error = setMetadataRes.error
+  var validProof: bool # out-param
+  let ffiOk = verify_with_roots(
+    g.rlnInstance, # RLN context created at init()
+    addr proofBuffer, # (proof + signal)
+    addr rootsBuffer, # valid Merkle roots
+    addr validProof # will be set by the FFI call
+    ,
+  )
 
-    return handleBlockRes
+  if not ffiOk:
+    return err("could not verify the proof")
+  else:
+    trace "Proof verified successfully !"
 
-  return wrappedCb
-
-proc startListeningToEvents(
-    g: OnchainGroupManager
-): Future[void] {.async: (raises: [Exception]).} =
-  initializedGuard(g)
-
-  let ethRpc = g.ethRpc.get()
-  let newBlockCallback = g.getNewBlockCallback()
-  g.runInInterval(newBlockCallback, DefaultBlockPollRate)
-
-proc batchAwaitBlockHandlingFuture(
-    g: OnchainGroupManager, futs: seq[Future[bool]]
-): Future[void] {.async: (raises: [Exception]).} =
-  for fut in futs:
-    try:
-      var handleBlockRes: bool
-      g.retryWrapper(handleBlockRes, "Failed to handle block"):
-        await fut
-    except CatchableError:
-      raise newException(
-        CatchableError, "could not fetch events from block: " & getCurrentExceptionMsg()
-      )
-
-proc startOnchainSync(
-    g: OnchainGroupManager
-): Future[void] {.async: (raises: [Exception]).} =
-  initializedGuard(g)
-
-  let ethRpc = g.ethRpc.get()
-
-  # static block chunk size
-  let blockChunkSize = 2_000.BlockNumber
-  # delay between rpc calls to not overload the rate limit
-  let rpcDelay = 200.milliseconds
-  # max number of futures to run concurrently
-  let maxFutures = 10
-
-  var fromBlock: BlockNumber =
-    if g.latestProcessedBlock > g.rlnContractDeployedBlockNumber:
-      info "syncing from last processed block", blockNumber = g.latestProcessedBlock
-      g.latestProcessedBlock + 1
-    else:
-      info "syncing from rln contract deployed block",
-        blockNumber = g.rlnContractDeployedBlockNumber
-      g.rlnContractDeployedBlockNumber
-
-  var futs = newSeq[Future[bool]]()
-  var currentLatestBlock: BlockNumber
-  g.retryWrapper(currentLatestBlock, "Failed to get the latest block number"):
-    cast[BlockNumber](await ethRpc.provider.eth_blockNumber())
-
-  try:
-    # we always want to sync from last processed block => latest
-    # chunk events
-    while true:
-      # if the fromBlock is less than 2k blocks behind the current block
-      # then fetch the new toBlock
-      if fromBlock >= currentLatestBlock:
-        break
-
-      if fromBlock + blockChunkSize > currentLatestBlock:
-        g.retryWrapper(currentLatestBlock, "Failed to get the latest block number"):
-          cast[BlockNumber](await ethRpc.provider.eth_blockNumber())
-
-      let toBlock = min(fromBlock + blockChunkSize, currentLatestBlock)
-      debug "fetching events", fromBlock = fromBlock, toBlock = toBlock
-      await sleepAsync(rpcDelay)
-      futs.add(g.getAndHandleEvents(fromBlock, toBlock))
-      if futs.len >= maxFutures or toBlock == currentLatestBlock:
-        await g.batchAwaitBlockHandlingFuture(futs)
-        g.setMetadata(lastProcessedBlock = some(toBlock)).isOkOr:
-          error "failed to persist rln metadata", error = $error
-        futs = newSeq[Future[bool]]()
-      fromBlock = toBlock + 1
-  except CatchableError:
-    raise newException(
-      CatchableError,
-      "failed to get the history/reconcile missed blocks: " & getCurrentExceptionMsg(),
-    )
-
-  # listen to blockheaders and contract events
-  try:
-    await g.startListeningToEvents()
-  except CatchableError:
-    raise newException(
-      ValueError, "failed to start listening to events: " & getCurrentExceptionMsg()
-    )
-
-method startGroupSync*(
-    g: OnchainGroupManager
-): Future[GroupManagerResult[void]] {.async.} =
-  ?resultifiedInitGuard(g)
-  # Get archive history
-  try:
-    await startOnchainSync(g)
-    return ok()
-  except CatchableError, Exception:
-    return err("failed to start group sync: " & getCurrentExceptionMsg())
+  return ok(validProof)
 
 method onRegister*(g: OnchainGroupManager, cb: OnRegisterCallback) {.gcsafe.} =
   g.registerCb = some(cb)
@@ -609,53 +536,27 @@ method init*(g: OnchainGroupManager): Future[GroupManagerResult[void]] {.async.}
     let metadata = metadataGetOptRes.get().get()
     if metadata.chainId != uint(g.chainId):
       return err("persisted data: chain id mismatch")
-
     if metadata.contractAddress != g.ethContractAddress.toLower():
       return err("persisted data: contract address mismatch")
-    g.latestProcessedBlock = metadata.lastProcessedBlock.BlockNumber
-    g.validRoots = metadata.validRoots.toDeque()
 
-  var deployedBlockNumber: Uint256
-  g.retryWrapper(
-    deployedBlockNumber,
-    "Failed to get the deployed block number. Have you set the correct contract address?",
-  ):
-    await wakuRlnContract.deployedBlockNumber().call()
-  debug "using rln contract", deployedBlockNumber, rlnContractAddress = contractAddress
-  g.rlnContractDeployedBlockNumber = cast[BlockNumber](deployedBlockNumber)
-  g.latestProcessedBlock = max(g.latestProcessedBlock, g.rlnContractDeployedBlockNumber)
   g.rlnRelayMaxMessageLimit =
     cast[uint64](await wakuRlnContract.MAX_MESSAGE_LIMIT().call())
 
   proc onDisconnect() {.async.} =
     error "Ethereum client disconnected"
-    let fromBlock = max(g.latestProcessedBlock, g.rlnContractDeployedBlockNumber)
-    info "reconnecting with the Ethereum client, and restarting group sync",
-      fromBlock = fromBlock
     var newEthRpc: Web3
     g.retryWrapper(newEthRpc, "Failed to reconnect with the Ethereum client"):
       await newWeb3(g.ethClientUrl)
     newEthRpc.ondisconnect = ethRpc.ondisconnect
     g.ethRpc = some(newEthRpc)
 
-    try:
-      await g.startOnchainSync()
-    except CatchableError, Exception:
-      g.onFatalErrorAction(
-        "failed to restart group sync" & ": " & getCurrentExceptionMsg()
-      )
-
   ethRpc.ondisconnect = proc() =
     asyncSpawn onDisconnect()
 
-  waku_rln_number_registered_memberships.set(int64(g.rlnInstance.leavesSet()))
   g.initialized = true
-
   return ok()
 
 method stop*(g: OnchainGroupManager): Future[void] {.async, gcsafe.} =
-  g.blockFetchingActive = false
-
   if g.ethRpc.isSome():
     g.ethRpc.get().ondisconnect = nil
     await g.ethRpc.get().close()
@@ -665,26 +566,13 @@ method stop*(g: OnchainGroupManager): Future[void] {.async, gcsafe.} =
 
   g.initialized = false
 
-proc isSyncing*(g: OnchainGroupManager): Future[bool] {.async, gcsafe.} =
-  let ethRpc = g.ethRpc.get()
-
-  var syncing: SyncingStatus
-  g.retryWrapper(syncing, "Failed to get the syncing status"):
-    await ethRpc.provider.eth_syncing()
-  return syncing.syncing
-
 method isReady*(g: OnchainGroupManager): Future[bool] {.async.} =
   initializedGuard(g)
 
   if g.ethRpc.isNone():
     return false
 
-  var currentBlock: BlockNumber
-  g.retryWrapper(currentBlock, "Failed to get the current block number"):
-    cast[BlockNumber](await g.ethRpc.get().provider.eth_blockNumber())
-
-  # the node is still able to process messages if it is behind the latest block by a factor of the valid roots
-  if u256(g.latestProcessedBlock.uint64) < (u256(currentBlock) - u256(g.validRoots.len)):
+  if g.wakuRlnContract.isNone():
     return false
 
-  return not (await g.isSyncing())
+  return true
diff --git a/waku/waku_rln_relay/protocol_metrics.nim b/waku/waku_rln_relay/protocol_metrics.nim
index 121727809..2210328f4 100644
--- a/waku/waku_rln_relay/protocol_metrics.nim
+++ b/waku/waku_rln_relay/protocol_metrics.nim
@@ -85,6 +85,7 @@ proc getRlnMetricsLogger*(): RLNMetricsLogger =
   var cumulativeProofsVerified = 0.float64
   var cumulativeProofsGenerated = 0.float64
   var cumulativeProofsRemaining = 100.float64
+  var cumulativeRegisteredMember = 0.float64
 
   when defined(metrics):
     logMetrics = proc() =
@@ -107,6 +108,9 @@ proc getRlnMetricsLogger*(): RLNMetricsLogger =
         let freshProofsRemainingCount = parseAndAccumulate(
           waku_rln_remaining_proofs_per_epoch, cumulativeProofsRemaining
         )
+        let freshRegisteredMemberCount = parseAndAccumulate(
+          waku_rln_number_registered_memberships, cumulativeRegisteredMember
+        )
 
         info "Total messages", count = freshMsgCount
         info "Total spam messages", count = freshSpamCount
@@ -116,5 +120,6 @@ proc getRlnMetricsLogger*(): RLNMetricsLogger =
         info "Total proofs verified", count = freshProofsVerifiedCount
         info "Total proofs generated", count = freshProofsGeneratedCount
         info "Total proofs remaining", count = freshProofsRemainingCount
+        info "Total registered members", count = freshRegisteredMemberCount
 
   return logMetrics
diff --git a/waku/waku_rln_relay/protocol_types.nim b/waku/waku_rln_relay/protocol_types.nim
index 97b1c34ea..c6f52e00b 100644
--- a/waku/waku_rln_relay/protocol_types.nim
+++ b/waku/waku_rln_relay/protocol_types.nim
@@ -52,6 +52,20 @@ type RateLimitProof* = object
   ## the external nullifier used for the generation of the `proof` (derived from poseidon([epoch, rln_identifier]))
   externalNullifier*: ExternalNullifier
 
+type UInt40* = StUint[40]
+type UInt32* = StUint[32]
+
+type
+  Field = array[32, byte] # Field element representation (256 bits)
+  RLNWitnessInput* = object
+    identity_secret*: Field
+    user_message_limit*: Field
+    message_id*: Field
+    path_elements*: seq[byte]
+    identity_path_index*: seq[byte]
+    x*: Field
+    external_nullifier*: Field
+
 type ProofMetadata* = object
   nullifier*: Nullifier
   shareX*: MerkleNode
diff --git a/waku/waku_rln_relay/rln/rln_interface.nim b/waku/waku_rln_relay/rln/rln_interface.nim
index cc468b124..27b3bbee9 100644
--- a/waku/waku_rln_relay/rln/rln_interface.nim
+++ b/waku/waku_rln_relay/rln/rln_interface.nim
@@ -130,6 +130,21 @@ proc generate_proof*(
 ## integers wrapped in <> indicate value sizes in bytes
 ## the return bool value indicates the success or failure of the operation
 
+proc generate_proof_with_witness*(
+  ctx: ptr RLN, input_buffer: ptr Buffer, output_buffer: ptr Buffer
+): bool {.importc: "generate_rln_proof_with_witness".}
+
+## rln-v2
+## "witness" term refer to collection of secret inputs with proper serialization
+## input_buffer has to be serialized as [ identity_secret<32> | user_message_limit<32> | message_id<32> | path_elements<Vec<32>> | identity_path_index<Vec<1>> | x<32> | external_nullifier<32> ]
+## output_buffer holds the proof data and should be parsed as [ proof<128> | root<32> | external_nullifier<32> | share_x<32> | share_y<32> | nullifier<32> ]
+## rln-v1
+## input_buffer has to be serialized as [ id_key<32> | path_elements<Vec<32>> | identity_path_index<Vec<1>> | x<32> | epoch<32> | rln_identifier<32> ]
+## output_buffer holds the proof data and should be parsed as [ proof<128> | root<32> | epoch<32> | share_x<32> | share_y<32> | nullifier<32> | rln_identifier<32> ]
+## integers wrapped in <> indicate value sizes in bytes
+## path_elements and identity_path_index serialize a merkle proof and are vectors of elements of 32 and 1 bytes respectively
+## the return bool value indicates the success or failure of the operation
+
 proc verify*(
   ctx: ptr RLN, proof_buffer: ptr Buffer, proof_is_valid_ptr: ptr bool
 ): bool {.importc: "verify_rln_proof".}
diff --git a/waku/waku_rln_relay/rln_relay.nim b/waku/waku_rln_relay/rln_relay.nim
index 268f1c93d..a42b04f8b 100644
--- a/waku/waku_rln_relay/rln_relay.nim
+++ b/waku/waku_rln_relay/rln_relay.nim
@@ -98,6 +98,7 @@ type WakuRLNRelay* = ref object of RootObj
   onFatalErrorAction*: OnFatalErrorHandler
   nonceManager*: NonceManager
   epochMonitorFuture*: Future[void]
+  rootChangesFuture*: Future[void]
 
 proc calcEpoch*(rlnPeer: WakuRLNRelay, t: float64): Epoch =
   ## gets time `t` as `flaot64` with subseconds resolution in the fractional part
@@ -252,6 +253,7 @@ proc validateMessage*(
     waku_rln_errors_total.inc(labelValues = ["proof_verification"])
     warn "invalid message: proof verification failed", payloadLen = msg.payload.len
     return MessageValidationResult.Invalid
+
   if not proofVerificationRes.value():
     # invalid proof
     warn "invalid message: invalid proof", payloadLen = msg.payload.len
@@ -467,9 +469,6 @@ proc mount(
   # Initialize the groupManager
   (await groupManager.init()).isOkOr:
     return err("could not initialize the group manager: " & $error)
-  # Start the group sync
-  (await groupManager.startGroupSync()).isOkOr:
-    return err("could not start the group sync: " & $error)
 
   wakuRlnRelay = WakuRLNRelay(
     groupManager: groupManager,
@@ -479,6 +478,11 @@ proc mount(
     onFatalErrorAction: conf.onFatalErrorAction,
   )
 
+  # track root changes on smart contract merkle tree
+  if groupManager of OnchainGroupManager:
+    let onchainManager = cast[OnchainGroupManager](groupManager)
+    wakuRlnRelay.rootChangesFuture = onchainManager.trackRootChanges()
+
   # Start epoch monitoring in the background
   wakuRlnRelay.epochMonitorFuture = monitorEpochs(wakuRlnRelay)
   return ok(wakuRlnRelay)